The present invention relates generally to the field of anti-sway bars and more specifically to a device that can be added to a traditional anti-sway bar that allows for remote control of the clamping pressure applied to the anti-sway bar.
Anti-sway bars are routinely attached between vehicles and trailers to control swaying of trailers as they are towed behind the vehicles. An anti-sway bar is typically attached to the rear of the towing vehicle and the front of the trailer, on or near the main trailer hitch assembly. Traditional anti-sway bars have three basic parts: a large hollow (outer) bar that attaches to the trailer; a smaller solid (inner) bar that attaches to the vehicle, the inner bar being able to slide in and out of the outer bar; and a hand crank that can clamp down on the inner bar by applying pressure to a flexible surface on the outer bar. When the hand crank is tightened the clamping pressure exerted on the interior bar greatly reduces the movement of the interior bar. Instead of moving freely in and out of the outer bar, it now takes a great deal of force to make the inner bar slide. When the hand crank is loosened the inner bar is able to slide in and out of the outer bar with very little force. This allows the anti-sway bar to extend and contract between different lengths.
Prior to getting on a highway, or soon after entering a highway, drivers must get out of their cars and tighten the hand crank on traditional anti-sway bars. This holds the anti-sway bar in at a semi-fixed length and prevents the towed trailer from swaying back and forth behind the vehicle. In a similar fashion, prior to leaving a highway or soon after leaving the highway, drivers must pull over, get out of their vehicles again and loosen the hand crank on traditional anti-sway bars. This allows the driver to maneuver their vehicle and trailer through city streets and gas stations. If a driver forgets to loosen his anti-sway bar prior to maneuvering around corners, or through parking lots, the anti-sway bar may either bend or break, and will likely cause damage to the towing equipment.
Leverage is a principle of engineering that involves the use of a lever and a fulcrum. A lever is a simple machine usually consisting of a rigid bar or rod that is designed to rotate about a fixed point, the fulcrum. The effect of any force applied to a lever is to rotate the lever about the fulcrum. The rotational force is in direct proportion to the distance between the fulcrum and the applied force. For example, a mass of 1 kg, 2 m from the fulcrum, can balance a mass of 2 kg at a distance of 1 m from the fulcrum. In the crowbar, one type of lever, a relatively small effort is applied at the end farthest from the fulcrum to lift a heavy weight that is close to the fulcrum.
Electric motors are devices that can convert electrical energy into mechanical energy, by electromagnetic means. Electric motors take advantage of the principle of electromagnetic reaction, first observed by the French physicist André Marie Ampère in 1820, which states that if a current is passed through a conductor located in a magnetic field, the field exerts a mechanical force on it. Both motors and generators consist of two basic units, the field, which is the electromagnet with its coils, and the armature, the structure that supports the conductors, which cut the magnetic field and carry the exciting current in a motor. The armature is usually a laminated soft-iron core around which conducting wires are wound in coils.
When current is passed through the armature of a DC motor, a torque is generated by magnetic reaction, and the armature revolves. The action of the commutator and the connections of the field coils of motors are precisely the same as those used for generators. The revolution of the armature induces a voltage in the armature windings. This induced voltage is opposite in direction to the outside voltage applied to the armature, and hence is called back voltage or counter electromotive force (emf). As the motor rotates more rapidly, the back voltage rises until it is almost equal to the applied voltage. The current is then small, and the speed of the motor will remain constant as long as the motor is not under load and is performing no mechanical work except that required to turn the armature. Under load the armature turns more slowly, reducing the back voltage and permitting a larger current to flow in the armature. The motor is thus able to receive more electric power from the source supplying it and to do more mechanical work.
The speed at which a DC motor operates depends on the strength of the magnetic field acting on the armature, as well as on the armature current. The stronger the field, the slower is the rate of rotation needed to generate a back voltage large enough to counteract the applied voltage. For this reason the speed of DC motors can be controlled by varying the field current.
Micro-switches are small electromechanical devices that can be used to selectively complete a circuit and or break (open) a circuit. Micro-switches use some received mechanical force to either complete or open the circuit. A micro-switch placed at the bottom of a garage door can be used to shut off the motor used to close the garage door when the bottom of the door comes into contact with the floor of the garage. A trigger on the micro-switch, usually a small strip of metal that extends out of the switch, touches the garage floor just prior to the arrival of the door. The garage floor applies pressure on the switch's trigger, which completes a circuit for sending an “off” signal to the garage door motor.
A screw or bolt is mechanical fastening device consisting essentially of an inclined plane wound spirally around a cylinder or a cone. The ridges formed by the winding planes are called threads, and depending on the intended use, the threads may be square, triangular, or rounded in cross section. The distance between two corresponding points on adjacent threads is called the pitch. If the thread is on the outside of a cylinder, it is called a screw or male thread, and if it is on the inside of a cylinder, it is called a female screw or nut. Screws and bolts used in machines employ a cylindrical shaft with a constant inner or minor diameter. The use of the screw as a simple device realizes the mechanical advantage of the inclined plane. This advantage is increased by the leverage usually applied to the turning of the cylinder, but is decreased by the high frictional losses in a screw-type system. The frictional forces, however, make screws effective fasteners.
Screws have a wide variety of uses. Screw jacks enable a person to raise heavy objects such as automobiles off the ground. The screw can also provide carefully controlled forward and backward motion relative to a connected machine member, as in a micrometer, which can measure distances to within 2.54 micrometers ( 1/10,000 in). The controlled motion is also used in various machine tools, such as lathes, where the cutting tools can be advanced with a high degree of precision.
A gear is a toothed wheel or cylinder that is used to transmit rotary motion from one part of a machine to another. Two or more gears, transmitting motion from one shaft to another, constitute a gear train. The simplest gear is the spur gear, a wheel with teeth cut across its edge parallel to the axis. Spur gears transmit rotating motion between two shafts or other parts with parallel axes. In simple spur gearing, the driven shaft revolves in the opposite direction to the driving shaft. If rotation in the same direction is desired, an idler gear is placed between the driving gear and the driven gear. The idler revolves in the opposite direction to the driving gear and therefore turns the driven gear in the same direction as the driving gear. In any form of gearing the speed of the driven shaft depends on the number of teeth in each gear. A gear with 10 teeth driving a gear with 20 teeth will revolve twice as fast as the gear it is driving, and a 20-tooth gear driving a 10-tooth gear will revolve at half the speed. By using a train of several gears, the ratio of driving to driven speed may be varied within wide limits.